Method and system for monitoring a transducer array in an ultrasound system

ABSTRACT

Methods and systems for monitoring a transducer array in an ultrasound probe are provided. One method includes acquiring ultrasound data using an ultrasound probe during an imaging mode of operation, wherein the ultrasound data includes echo information. The method further includes comparing the echo information from a plurality of transducer elements of a transducer array of the ultrasound probe during the imaging mode of operation, wherein the echo information is non-beamformed signal data. The method also includes determining non-uniformity information for the transducer array using the compared echo information during the imaging mode of operation.

This application is a Reissue of application Ser. No. 13/362,890, whichis also an application for reissue of U.S. Pat. No. 8,792,295 B2.

BACKGROUND OF THE INVENTION

Diagnostic medical imaging systems typically include a scan portion anda control portion having a display. For example, ultrasound imagingsystems usually include ultrasound scanning devices, such as ultrasoundprobes having transducers that are connected to an ultrasound system tocontrol the acquisition of ultrasound data by performing variousultrasound scans (e.g., imaging a volume or body). The ultrasoundsystems are controllable to operate in different modes of operation toperform the different scans. The signals received at the probe are thencommunicated and processed at a back end.

The transducers in medical ultrasound probes typically contain array(s)having a large number of transducer elements, which may includeassociated per-element electronic circuits. The probes may bemechanically fragile, so it is common to experience degradation or evendefects of some elements during the lifetime of the probe. One cause offailures is mechanical shock, for example if the probe is dropped on thefloor. Other causes of failures may be the failure of electricalinterconnects, partial delamination of the transducer lens or otheracoustic layers, local depolarization of piezoelectric material, etc.Element degradation will deteriorate the quality of the image producedby the probe. In conventional systems, it is difficult or impossible todiagnose the array uniformity (or “health state”) of a probe without useof special test equipment and/or test modes of the system. These knowsystems include the use of special test circuitry, use of special testobjects, or use of special test modes. In some systems, special testsoftware may be provided on the console, for example that includes“imaging” using only a single element of the probe, and having theoperator step through the array under test one element at a time. Thistest is cumbersome, and, while it can be used to show the presence ofelements that are defective, it is hard to obtain quantitativeinformation from the test. Typically such a test would be performed by aservice technician, and not by a sonographer. Thus, these known methodsfor diagnosis, if even possible to perform, are very time consuming andcan be costly.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with one embodiment, a method for monitoring a transducerarray of an ultrasound probe when it is performing its normal imagingoperation is provided. The method includes acquiring ultrasound datausing an ultrasound probe during an imaging mode of operation, whereinthe ultrasound data includes echo information. The method furtherincludes comparing the echo information from a plurality of transducerelements of a transducer array of the ultrasound probe during theimaging mode of operation, wherein the echo information isnon-beamformed signal data. The method also includes determiningnon-uniformity information for the transducer array using the comparedecho information during the imaging mode of operation.

In accordance with another embodiment, an ultrasound system is providedthat includes an ultrasound probe having a transducer array foracquiring ultrasound data including echo information during an imagingmode of operation and a memory for storing received echo information.The ultrasound system further includes a monitoring module for comparingthe echo information from a plurality of transducer elements of thetransducer array of the ultrasound probe during the imaging mode ofoperation, wherein the stored echo information is non-beamformed signaldata. The monitoring module also determines non-uniformity informationfor the transducer array using the compared echo information during theimaging mode of operation.

In accordance with yet another embodiment, a non-transitory computerreadable storage medium for monitoring a transducer array of anultrasound probe using a processor during an imaging mode of operationis provided. The non-transitory computer readable storage mediumincludes instructions to command the processor to compare echoinformation from a plurality of transducer elements of a transducerarray of an ultrasound probe during the imaging mode of operation,wherein the echo information is non-beamformed signal data. Thenon-transitory computer readable storage medium includes instructions tofurther command the processor to determine non-uniformity informationfor the transducer array using the compared echo information during theimaging mode of operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of an ultrasound system formed inaccordance with various embodiments.

FIG. 2 is a block diagram illustrating an ultrasound processing workflow performed in accordance with various embodiments.

FIG. 3 is a flowchart of a method for monitoring a transducer array inaccordance with various embodiments.

FIG. 4 is an exemplary graph that may be provided in accordance withvarious embodiments.

FIG. 5 is a diagram of an exemplary report that may be provided inaccordance with various embodiments.

FIG. 6 is a block diagram of an ultrasound system in connection withwhich various embodiments may be implemented.

FIG. 7 is a block diagram of an ultrasound processor module of theultrasound system of FIG. 6 formed in accordance with variousembodiments.

FIG. 8 is a diagram illustrating a miniaturized ultrasound system inwhich various embodiments may be implemented.

FIG. 9 is a diagram illustrating a hand carried or pocket-sizedultrasound imaging system in which various embodiments may beimplemented.

FIG. 10 is a diagram illustrating a console type ultrasound imagingsystem in which various embodiments may be implemented.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing summary, as well as the following detailed description ofcertain embodiments will be better understood when read in conjunctionwith the appended drawings. To the extent that the figures illustratediagrams of the functional blocks of various embodiments, the functionalblocks are not necessarily indicative of the division between hardwarecircuitry. Thus, for example, one or more of the functional blocks(e.g., processors or memories) may be implemented in a single piece ofhardware (e.g., a general purpose signal processor or a block of randomaccess memory, hard disk, or the like) or multiple pieces of hardware.Similarly, the programs may be stand alone programs, may be incorporatedas subroutines in an operating system, may be functions in an installedsoftware package, and the like. It should be understood that the variousembodiments are not limited to the arrangements and instrumentalityshown in the drawings.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” are not intended to beinterpreted as excluding the existence of additional embodiments thatalso incorporate the recited features. Moreover, unless explicitlystated to the contrary, embodiments “comprising” or “having” an elementor a plurality of elements having a particular property may includeadditional elements not having that property.

Various embodiments provide systems and methods for monitoring theresponse of the individual transducer elements (or groups of elements)of an ultrasound probe using the ultrasound console, during normalscanning on the human body. By practicing various embodiments, and atechnical effect of at least one embodiment, is that monitoring and/ordiagnosis of an ultrasound transducer array without use of special testcircuitry/test modes or test phantoms may be provided.

It should be noted that various embodiments described herein thatgenerate or form images may include processing for forming images thatin some embodiments includes beamforming and in other embodiments doesnot include beamforming. For example, an image can be formed withoutbeamforming, such as by multiplying the matrix of demodulated data by amatrix of coefficients so that the product is the image, and wherein theprocess does not form any “beams”. Also, forming of images may beperformed using channel combinations that may originate from more thanone transmit event (e.g., synthetic aperture techniques).

In various embodiments, ultrasound processing to form images isperformed, for example, including ultrasound beamforming, such asreceive beamforming, in software, hardware, or a combination thereof.One implementation of an ultrasound system having a software beamformerarchitecture formed in accordance with various embodiments is shown inFIG. 1, which illustrates a simplified block diagram of an ultrasoundsystem 30. The ultrasound system 30 is configured to acquire ultrasounddata using a probe 32 having a transducer array 40 (with a plurality oftransducer elements 42), wherein transmission and receptionfunctionality, such as transmission and reception of ultrasound signalsare provided by a front end 34. In another embodiment, the probe 32 maycontain electronics, for example, for performing partial beamforming ofgroups adjacent elements (such as using a SAP—Sub Array Processor)and/or transmitter electronics. In the illustrated embodiment, the frontend 34 does not include a hardware implemented receive beamformer.However, it should be noted that a hardware implemented receivebeamformer optionally may be provided to perform, for example, partialbeamforming of groups of channels data 38. The front end 34 generallyincludes a transmitter/receiver, which may be implemented in, forexample, an application specific integrated circuit (ASIC) or afield-programmable gate array (FPGA).

The transducer elements 42 may have a one-dimensional, two-dimensional,or three dimensional arrangement. Additionally, different types oftransducer arrays 40 may be provided, such as a linear array or anarcuate array.

The front end 34 is connected to a back end 36, for example, via one ormore communication lines (or channels data) 38, which may include one ormore buses, such as a Peripheral Component Interconnect Express (PCIe)bus or other bus (e.g., a high bandwidth bus typically having severalGB/sec. transfer rate). Alternately the communication channel may be awireless link. The communication line(s) 38 communicates ultrasound datafrom the front end 34 to the back end 36, and may include one or moredata channels. The data that is communicated from the front end 34 tothe back end 36 is generally a digitized and optionally transformedversion of the channel data as acquired by the probe 32. Thetransformation may include, for example, filtering/decimation, complexdemodulation, or other standard signal processing operations.

The back end 36 generally includes processing units, which include asoftware implemented beamformer and an IQ/RF processor as described inmore detail below. The processing functions may be performed by ageneral purpose CPU or GPU.

In various embodiments, the data transmitted from the front end 34 tothe back end 36 is used to monitor the transducer elements 42 inreal-time, for example, as the probe 32 is operating, such as scanningan object of interest. As described in more detail herein, the data isused to monitor an array response or uniformity of the transducer array40 in real-time (e.g., during normal scanning operations). Inparticular, the various embodiments may use signals for all or a subsetof the transducer elements 42 to perform real-time analysis of thetransducer array 40.

In some embodiments, the ultrasound system 30 operates to performreal-time three-dimensional (3D) or four-dimensional (4D) scanning thattransmits and/or acquires multiple beams simultaneously or concurrently.The ultrasound system 30 in various embodiments includes the softwarebeamformer implemented in a general purpose processor (e.g., CPU or GPU)that receives data from a plurality of channels 38 corresponding to thetransducer elements 42. Thus, data transfer from all or a subset of thechannels 38 is provided in some embodiments for use in monitoring oranalysis of the transducer array 40, which may be performed by amonitoring module 44 in the back end 36. The transferred data may thenbe beamformed with the general purpose processor performing, forexample, beamforming calculations using any suitable beamforming method.

It should be noted that software beamforming includes performing anytype of beamforming technique, which may include performing beamformingtechniques in software that can be performed in hardware. It also shouldbe noted that when reference is made herein to beamforming techniques,this generally refers to any type of image forming that may be performedby the ultrasound system. Accordingly, the various embodiments may beimplemented in connection with forming images whether or not beams areformed.

FIG. 2 illustrates an ultrasound processing work flow 48 performed inaccordance with various embodiments for monitoring or analyzing theoperation of the transducer elements 42 of the transducer array 40. Inparticular, acquired ultrasound data 50 is received via a plurality ofreceive channels 52. The acquired ultrasound data 50 is non-beamformed(or optionally sub-array beamformed) data in various embodiments, whichmay be stored temporarily, such as for a time frame on the order of thatneeded to align the phase fronts of the different signal channels (e.g.,1-15 micro-seconds) for use in performing monitoring and analysisoperations. Thereafter, the acquired ultrasound data 50 is beamformedusing a software beamformer.

The temporarily stored acquired ultrasound data 50 is used to monitor anarray response to determine an array uniformity in real-time. Forexample, in one embodiment, the response of the individual transducerelements 42 (or groups/sets of the transducer elements 42, or outputfrom electronics associated with one or more elements of the transducerarray 40) are monitored during normal scanning operation of the probe32, such as when scanning a patient. The monitoring of the responsegenerally includes analyzing the echo signals from all or a subset ofthe transducer elements 42. In various embodiments, the analysisincludes a comparison of the amplitudes from adjacent transducerelements 42. Using the comparison, and as described in more detailherein, an array response 54 is monitored, such as to determine an arrayuniformity.

The monitoring of the transducer array 40 using the echo responses mayinclude using apriori response data to predict image qualitydeterioration as described in more detail herein. Additionally, the timeperiod for analysis (e.g., averaging response data) may be varied andthresholding may be used to determine when a valid output signalsuitable for analysis is detected. The results of the monitoredtransducer array 40 may be used to provide different outputs or may beused as an input to other processes. For example, the monitoring resultsmay be used to generate a report or provide feedback useful inevaluating the condition of the probe 32 and whether, for example, anyfailure of transducer elements 42 may be as a result of misuse (e.g., anexcessive acceleration event such as dropping or hitting of the probe32). Additionally, the monitoring results may be used to provideadaptive compensation to improve or even fully correct imagingperformance in the case of significant array non-uniformity. Themonitoring results also may be stored for future use, such as fortrending. In general, the results of the analysis, for example, thecomparison of the response of the transducer elements 42 may be used inany way for evaluation of probe operation or to compensate fornon-uniformities in the detector array 40. In some cases, such as inpiezoelectric accidental de-poling, the various embodiments mayincorporate some probe repair capability. For example, correctionsoftware may be provided that incorporates control of all (or a subsetof) potential risk associated with probe characteristics changesrelative to relevant safety regulations.

Various embodiments provide a method 60 as shown in FIG. 3 formonitoring a transducer array, for example, the transducer array 40,which includes analyzing the operation of the transducer elements of thetransducer array. The method 60 including the monitoring of thetransducer array is performed during an imaging mode of operation of theprobe, for example, when the probe is performing a normal imagingoperation. Thus, the method 60 in various embodiments allows formonitoring the probe while the probe is performing a particularoperation, for example, when connected to an ultrasound console to scantissue (e.g., human tissue) and produce images. Accordingly, in variousembodiments, no test mode or special test object is needed or used.

The method 60 includes acquiring ultrasound data at 62, which includesacquiring echo signals from the ultrasound probe (e.g., the probe 32).In various embodiments, the acquired echo signals are signals asacquired by the probe, such that the ultrasound data is in anon-beamformed and/or non-image formed state. In one embodiment, forexample, the ultrasound data is the signals received directly from thetransducer elements of the transducer array, or some transformed versionof those signals. Thus, the probe acquiring the ultrasound data does notbeamform the data (except some embodiments that may use Sub-ArrayBeamforming in the probe; in such cases the ultrasound data correspondsto the output from the Sub-Array Processors within the probe). Instead,the ultrasound data is temporarily stored for use in the method 60before being beamformed or otherwise processed by a software beamformer.

The method 60, in one embodiment, preprocesses the received raw signalsbefore analyzing the signals as described below. For example, the rawsignals are preprocessed to determine when the transducer is providing avalid output suitable for detection. In one embodiment, automaticthresholding of signal levels, or manually through an operator input isused to identify signals that exceed, for example, a minimum signalamplitude, such that the signal is a valid echo signal and not, forexample, noise or crosstalk. In one embodiment with a manualidentification, the operator may push a button when a “good” signal ispresent. Alternately, the ultrasound console may determine that a goodsignal is present when the operator performs certain operations (e.g.,hitting the “store image” button). Alternately, the methods described inU.S. Pat. No. 8,002,704 may be used as an indication for good probecontact with the body, and, therefore, valid echo data. Still anotherexample is to use the echoes from a transducer/lens ringdown, such asdescribed in U.S. Pat. No. 5,517,994. These echoes are always present,but may be challenging to monitor reliably because the echoes occur soclose to the large transmit pulse. In some advanced front-endconfiguration transducers, impedance may also be monitored.

Thereafter, the acquired echo signals are analyzed, for example, theecho signals are processed to monitor an array uniformity in real-timewhile the probe is scanning. For example, in one embodiment, the echosignals, which are the raw signals, are compared. Thus, the acquiredsignals before beamforming are compared. In particular, the echo signalsfrom a plurality or all of the probe elements are compared in real-time,during normal scanning, without the use of special test objects, tomeasure and monitor array uniformity. In one embodiment, echo signalsfrom adjacent probe elements are compared.

Thus, in various embodiments using ultrasound systems with softwarebeamformers, the main echo processing unit has real-time access to theindividual signals from the transducer elements, and the method 60monitors the signals from the individual elements during normal scanning(e.g., compares signals from different transducer elements). A probe inperfect working condition is expected to have transducer elements thatyield signals of similar amplitudes and predictable delay/phasecharacteristics during normal scanning. Accordingly, signals from anygiven element may be compared with the signals from neighboring oradjacent elements during normal scanning to determine variances.

For example, amplitudes of the signals from adjacent probe elements arecompared, such as to determine if any exceed a predetermined differencevariance. Alternately, for probes containing Sub-Array Beamformers (alsoreferred to as “smart probes”), signals from a group of probe elementscorresponding to the outputs of the Sub-Array Beamformers (SAPs) arecompared. It should be noted that although the method 60 is described inconnection with probes without SAPs, the method 60 may similarly be usedwith probes having SAPs.

The comparison in some embodiments may be performed using a simplecomparison of the average echo amplitude for selected regions ofinterest. Alternately, in some embodiments correlation techniquesbetween signals from adjacent elements may be used. In this case, and asdescribed in more detail below, the element signals may be corrected forthe expected time-of-flight difference for signals from a certain pointin space (also referred to as beamforming delays) prior to performingthe correlation. As another variation, the entire or part of thiscorrection may be performed on the correlated result. The correlationanalysis may be used to extract systematic time-of-flight errors for theprobe, etc.

The measurements performed by the method 60 including the comparison ofthe echo signals may be performed in different ways. For example, thecomparison at 64 may be performed with a relatively short averagingtime, or the raw measurement results may be averaged over multiplemeasurement sessions, which can improve reliability. The averagemagnitude, the accumulated sum of signal magnitude or other statisticalmeasures of the individual channel signals can be calculated over a verylarge time window compared to daily use of the machine such as toeffectively average out the effects of different scanning views,different subjects or different machine setups, such that channeldeficiencies can be more easily identified. It should be noted that theoverall gain level summed over all channels also may be accumulated overa very large time scale and the accumulated value or the sliding averageover this “historical” time scale may be monitored to identify a generalweakening of the overall probe signal. The statistical window used invarious embodiments has a time period such that scanning differentsubjects or scanning in air can be assumed to be averaged out. It alsoshould be noted that in various embodiments, some function of the data,namely the channel data may be averaged, such as a relative channelsensitivity or other function related to the array sensitivity.

Thus, using the comparison at 64, non-uniformity information for thetransducer array is determined at 66. For example, changes in arrayuniformity may be tracked over time, thereby allowing the ultrasoundconsole to adaptively change the way the probe is controlled asdescribed in more detail below. Accordingly, the deterioration of imagequality introduced by the change in array characteristics may be reducedor minimized.

The non-uniformity information is then used at 68 to provide one or moreoutputs or perform additional operations. Thus, an ultrasound system ofvarious embodiments that is capable of measuring and comparing probeelement data may use the data in different ways, which will now bedescribed in connection with various exemplary additional steps for themethod 60.

For example, probe health may be reported at 70. For example, changes inprobe health may be reported as a status to the operator. In oneembodiment, a warning (e.g., an audible or visual notification), orquantitative information (e.g., numbers or graphs) may be generated andpresented to an operator, for example, on a display of the ultrasoundsystem.

The method 60 may also include compensating for the determinednon-uniformities at 72. For example, alternately or additionally,adaptive compensation for element non-uniformities through changes inscanner setup may be provided. In one embodiment, a delay error may becompensated through changes in transmit or receive delays (tx and/or rxdelays) in the beamforming. For example, a weak element may have a gainincrease applied thereto on receive, and/or use a stronger excitationsignal on transmit. Alternately the gain of immediate neighbortransducer elements may be increased if the transducer element is notfunctioning, not properly functioning, or “dead”, such as, for exampleas described in U.S. Pat. No. 5,676,149.

The method additionally may include quantifying an impact of thenon-uniformities at 74. For example, knowledge of the response of theindividual array elements optionally allows for the prediction of imagequality deterioration associated with that performance. In oneembodiment, suitable simulation software and/or decision criteria may beused such that an “intelligent decision” may be made to determine if thecurrent probe health is such that the probe should be replaced. Itshould be noted that knowledge of the individual element responses mayalso enable the console to adaptively compensate for changes in arraynon-uniformities (as described above in connection with step 72),thereby reducing or minimizing the image quality deteriorationoriginating from a given probe health state.

For example, alternately or additionally, the data (with or without thecompensations from steps 72 and 74) may be used as an input to asoftware simulator that quantifies the impact of the given probe healthstatus on the transmit and/or receive beam response of the transducer.The simulator results may be used to identify failures that representimage quality deterioration and that also have a greater likelihood ofinterfering with the overall diagnostic use of the probe.

It should be noted that the health state of the probe at the time of aparticular patient examination, or some performance index relating tothe probe/system combination, where compensation mechanisms have beentaken into account, may optionally be stored as a field in a patientexamination report. This may serve, for example, as proof that theinvestigation was performed with a system in good working condition.

The measurement data also may be combined with other information toprovide feedback at 76. For example, the probe may contain anacceleration or shock sensor, for example as described in U.S. PatentApplication Publication 2006/0004290, which may be any suitable and/orcommercially available device. In this embodiment, if the ultrasoundconsole detects that:

a. the probe has been dropped (from the state of the shock sensor,optionally in combination with temporal information as to when the shockoccurred), and

b. this drop coincides with a deterioration of array uniformity, thenthis information may be provided as feedback (e.g., visual notification)to the operator, which may reduce the likelihood for similar events inthe future. If such an event occurs within the warranty period of theprobe, probe abuse may be concluded and the warranty of the probe may bevoided.

Additionally, the method 60 may include creating trend information at78. For example, the determined non-uniformity information may also bestored for future use, either in the ultrasound console and/or on amemory device in the probe assembly. Accordingly, trend information maybe created that tracks the performance of the probe over time even ifthe probe is moved between different consoles.

Also, consoles that implement the method 60 may adaptively usecompensation techniques to reduce or minimize the image quality impactof array non-uniformities that develop over the time of probe usage.

The non-uniformity information may be stored at 80, such as forsubsequent use as described above or for later retrieval. In oneembodiment, the information is stored such that the information isuniquely linked to the probe that is being monitored, tested orinvestigated, for example, by including or combining probe type withprobe serial number information or some other unique identificationlabel. For example, the stored non-uniformity information (e.g., probehealth information) may be accessed (e.g., remotely accessed) by servicetechnicians over a network. Additionally, updated information as afunction of probe life may be stored at 82, such as updatednon-uniformity information.

The non-uniformity information may be compiled and/or presented in anysuitable manner. For example, as shown in FIG. 4, a graph 90 may begenerated, which may be displayed to a user. The x-axis corresponds totime and the y-axis corresponds to a probe property, such as alikelihood of failure, probe imaging performance on an absolute orrelative scale, etc. The graph 90 includes a curve 92 that correspondsto a change in the likelihood of failure (in the past) and predictedlikelihood of failure (in the future) using the determinednon-uniformity information and the method 60. The graph 90 may alsoinclude a curve portion 94 that represents and shows a change in thepredicted probe property (e.g., useful life). In this case, the curveportion 94 illustrates that the likelihood of probe failure is on anincreased track and also identifies a point 96 on the curve 92corresponding to an identified or recorded event. In this case, theevent may be a dropped probe, after which the likelihood of failureincreased more rapidly, which may have resulted from damage to sometransducer elements that may be determined based on the non-uniformityinformation.

As another example, the non-uniformity information may be presented in areport 100 as shown in FIG. 5. The report 100 may be displayed or inhard copy form. The report 100 may include any information derived ordetermined from the measured non-uniformity information. For example,the report may identify the number of failed transducer elements, thenumber of transducer elements being compensated, the predicted remainingprobe life, etc. In general, any desired or required information may beprovided.

Thus, various embodiments may provide an ultrasound console thatmonitors the response of the individual transducer elements (or groupsof transducer elements) during normal scanning, without the use ofspecial test circuitry or test phantoms. The probe health optionally maybe reported to the ultrasound operator, for example in the form of anindicator on a display, or as a warning to the operator if the probeperformance drops below a predetermined acceptance threshold, as aperformance trend vs. time as described herein, or other suitableformats. Alternately, the probe health information based on the measuredtransducer non-uniformity may be used to generate information that canbe accessed by a service technician. This information may be accessed,for example, during scheduled maintenance sessions, either locally orover a network. Also, information about an individual probe'sperformance and/or performance trend may also be stored within a memorydevice that is located either in the system, and/or as a part of theprobe assembly. The latter method allows the information to be accessedand used by other systems that may not have the monitoring capabilitiesof the various embodiments.

It should be noted that the various embodiments may also be used inconnection with special test objects (e.g., phantoms) or test circuitry.Also, it should be noted that the receiver channels and the transmitterchannels of the probe in various embodiments are initially calibrated.For example, the gains of all receiver channels are calibrated to bewithin a determined tolerance or variance, such as within a fraction ofa dB. For example, the receiver gain may be calibrated duringmanufacture of the ultrasound system. Alternately, gain characteristicsmay be stored on the console (e.g., generated during manufacturing), andtaken into account during both the array measurement and in thecorrection of the beamforming. It should be noted that a similarcorrection may be performed on the transmit side.

The various embodiments may be implemented in an ultrasound system 200as illustrated in FIG. 6. It should be noted that the variousembodiments may be implemented in different portions or components ofthe ultrasound system 200.

In particular, FIG. 6 is a block diagram showing an ultrasound system200 that operates to perform transducer array monitoring in accordancewith one or more embodiments described herein and also includes softwarebeamforming. The monitoring operation and the software beamforming maybe implemented, for example, by a processor executing instructions on atangible, non-transitory computer readable medium. The ultrasound system200 is configured to acquire ultrasound data using a probe 206, whereintransmission and reception of ultrasound signals are provided by a frontend 201, which as illustrated does not include a hardware implementedreceive beamformer. However, it should be noted that a hardwareimplemented receive beamformer optionally may be provided to performsome beamforming, for example partial beamforming. The front end 201 isconnected to a back end 203 via a plurality of data channels thatcommunicate ultrasound element data from the front end 201 to the backend 203.

The ultrasound system 200 is capable of electrical or mechanicalsteering of a sound beam (such as in 3D space) and is configurable toacquire information corresponding to a plurality of 2D representationsor images (or optionally 3D and 4D images) of a region of interest (ROI)in a subject or patient, which may be defined or adjusted as describedin more detail herein. The ultrasound system 200 is configurable toacquire 2D images, for example, in one or more planes of orientation.

The ultrasound system 200 includes a transmitter 202 that, under theguidance of a beamformer (transmit beamformer), drives an array ofelements 204 (e.g., piezoelectric elements) within a probe 206 to emitpulsed ultrasonic signals into a body. A variety of geometries may beused. The ultrasonic signals are back-scattered from structures in thebody, like blood cells or muscular tissue, to produce echoes that returnto the elements 204. The echoes are received by a receiver 208 and thencommunicated to an ADC 210 and demodulator 212, which may be differentcomponents or implemented in a single component, for example, in anASIC. The complex demodulator 212 performs digital demodulation, andoptionally filtering and decimation as described in more detail herein.The demodulated (or down-sampled) ultrasound data may be stored in amemory 214, such as temporarily for access by the monitoring module 44to perform one or more embodiments described herein. In anotherembodiment, the monitoring module 44 may be an integrated part of thebeamformer 230 (also referred to as a beamformer module).

The complex demodulator 212, demodulates the RF signal to form IQ datapairs representative of the echo signals, which in various embodimentshave a reduced data transfer rate that the transfer rate of the ADC 210.Alternately, the complex demodulator 212 may be removed or replaced bysome other signal processing algorithm. The RF or IQ element data maythen be routed directly to the memory 214 for storage. In someembodiments, a hardware receive beamformer optionally may be provided inthe front end 201. In an alternative embodiment, the probe 206optionally includes a 1D or 2D array with sub-aperture receivebeamforming inside the probe.

The output signals from the beamformer 230 may be processed by amid-processor 236 into different data types, e.g. B-mode, color Doppler(velocity/power/variance), tissue Doppler (velocity), and Dopplerenergy, for multiple scan planes or different scanning patterns. In oneembodiment (as illustrated), the mid-processor 236 is embodied insoftware as an I,Q/RF processor and image processor. The processor 236(also referred to as the ultrasound processor module) may generatetissue Doppler data for multi-scan planes. The processor 236 also maygather the information (e.g. I,Q data pairs, B-mode, color Doppler,tissue Doppler, and Doppler energy information) related to multiple dataslices and stores the data information, which may include time stamp andorientation/rotation information, in the memory 214.

The ultrasound system 200 also includes a processor 216 to furtherprocess the output of the processor 236 and prepare frames of ultrasoundinformation for display on display 218, with the image quality orresolution improved in some embodiments as described in more detailherein. The processor 216 is adapted to perform one or more processingoperations according to a plurality of selectable ultrasound modalitieson the acquired ultrasound data. The processor 216 also performsbeamforming operations using a beamformer 230, which in one embodiment(as illustrated) is software. The processor 216 is connected to a userinterface 224 (which may include a mouse, keyboard, touch panel, etc.)that may control operation of the processor 216 as explained below inmore detail. A display 218 includes one or more monitors that presentpatient information, including diagnostic ultrasound images to the userfor diagnosis and analysis, as well as monitoring information asdescribed herein. One, two or all of the memory 214, a memory 223 (shownin FIG. 7) and the memory 222 may store data corresponding totwo-dimensional (2D) or three-dimensional (3D) data sets of theultrasound data, where such 2D and 3D data sets are accessed to present2D (and/or 3D or 4D images), which may be in different states ofprocessing. The images may be modified and the display settings of thedisplay 218 also manually adjusted using the user interface 224.

The beamformer 230 shown connected to the processor 216 may be softwarerunning on the processor 216 or hardware provided as part of theprocessor 216. The beamformer 230, performs receive beamforming asdescribed in more detail herein and outputs a signal of I,Q data pairs.The beamformer 230 may phase shift, delay, apodize and sum each elementsignal with other element signals. The summed signals represent echoesfrom the ultrasound beams or lines.

It should be noted that although the various embodiments may bedescribed in connection with an ultrasound system, the methods andsystems are not limited to ultrasound imaging or a particularconfiguration thereof. The various embodiments may be implemented inconnection with different types of imaging systems, including, forexample, multi-modality imaging systems having an ultrasound imagingsystem and one of an x-ray imaging system, magnetic resonance imaging(MRI) system, computed-tomography (CT) imaging system, positron emissiontomography (PET) imaging system, among others. Further, the variousembodiments may be implemented in non-medical imaging systems, forexample, non-destructive testing systems such as ultrasound weld testingsystems or airport baggage scanning systems.

FIG. 7 illustrates an exemplary block diagram of an ultrasound processormodule 236, which may be embodied as the processor 216 of FIG. 6 or aportion thereof. The ultrasound processor module 236 is illustratedconceptually as a collection of sub-modules, but may be implementedutilizing any combination of dedicated hardware boards, DSPs,processors, etc. Alternatively, the sub-modules of FIG. 7 may beimplemented utilizing an off-the-shelf PC with a single processor ormultiple processors, with the functional operations distributed betweenthe processors, for example also including a Graphics Processor Unit(GPU). As a further option, the sub-modules of FIG. 7 may be implementedutilizing a hybrid configuration in which certain modular functions areperformed utilizing dedicated hardware, while the remaining modularfunctions are performed utilizing an off-the shelf PC and the like. Thesub-modules also may be implemented as software modules within aprocessing unit.

The operations of the sub-modules illustrated in FIG. 7 may becontrolled by a local ultrasound controller 250 or by the processormodule 236. The sub-modules 252-264 perform mid-processor operations.The ultrasound processor module 236 may receive ultrasound data 270 inone of several forms. In the embodiment of FIG. 9, the receivedultrasound data 270 constitutes I,Q data pairs representing the real andimaginary components associated with each data sample. The I,Q datapairs are provided to one or more of a color-flow sub-module 252, apower Doppler sub-module 254, a B-mode sub-module 256, a spectralDoppler sub-module 258 and an M-mode sub-module 260. Optionally, othersub-modules may be included such as an Acoustic Radiation Force Impulse(ARFI) sub-module 262 and a Tissue Doppler (TDE) sub-module 264, amongothers.

Each of sub-modules 252-264 are configured to process the I,Q data pairsin a corresponding manner to generate color-flow data 272, power Dopplerdata 274, B-mode data 276, spectral Doppler data 278, M-mode data 280,ARFI data 282, and tissue Doppler data 284, all of which may be storedin a memory 290 (or memory 214 or memory 222 shown in FIG. 8)temporarily before subsequent processing. For example, the B-modesub-module 256 may generate B-mode data 276 including a plurality ofB-mode image planes, such as in a biplane or triplane image acquisitionas described in more detail herein.

The data 272-284 may be stored in the memory 290, for example, as setsof vector data values, where each set defines an individual ultrasoundimage frame. The vector data values are generally organized based on thepolar coordinate system. Alternately or additionally the data may bestored as beamformed I,Q data in the memory 223.

A scan converter sub-module 292 accesses and obtains from the memory 290the vector data values associated with an image frame and converts theset of vector data values to Cartesian coordinates to generate anultrasound image frame 295 formatted for display. The ultrasound imageframes 295 generated by the scan converter sub-module 292 may beprovided back to the memory 290 for subsequent processing or may beprovided to the memory 214 or the memory 222.

Once the scan converter sub-module 292 generates the ultrasound imageframes 295 associated with, for example, B-mode image data, and thelike, the image frames may be restored in the memory 290 or communicatedover a bus 296 to a database (not shown), the memory 214, the memory 222and/or to other processors.

The scan converted data may be converted into an X,Y format for videodisplay to produce ultrasound image frames. The scan convertedultrasound image frames are provided to a display controller (not shown)that may include a video processor that maps the video to a grey-scalemapping for video display. The grey-scale map may represent a transferfunction of the raw image data to displayed grey levels. Once the videodata is mapped to the grey-scale values, the display controller controlsthe display 218 (shown in FIG. 6), which may include one or moremonitors or windows of the display, to display the image frame. Theimage displayed in the display 118 is produced from image frames of datain which each datum indicates the intensity or brightness of arespective pixel in the display.

Referring again to FIG. 7, a 2D video processor sub-module 294 combinesone or more of the frames generated from the different types ofultrasound information. For example, the 2D video processor sub-module294 may combine a different image frames by mapping one type of data toa grey map and mapping the other type of data to a color map for videodisplay. In the final displayed image, color pixel data may besuperimposed on the grey scale pixel data to form a single multi-modeimage frame 298 (e.g., functional image) that is again re-stored in thememory 290 or communicated over the bus 296. Successive frames of imagesmay be stored as a cine loop in the memory 290 or memory 222 (shown inFIG. 6). The cine loop represents a first in, first out circular imagebuffer to capture image data that is displayed to the user. The user mayfreeze the cine loop by entering a freeze command at the user interface224. The user interface 224 may include, for example, a keyboard andmouse and all other input controls associated with inputting informationinto the ultrasound system 200 (shown in FIG. 8).

A 3D processor sub-module 299 is also controlled by the user interface124 and accesses the memory 290 to obtain 3D ultrasound image data andto generate three dimensional images, such as through volume renderingor surface rendering algorithms as are known. The three dimensionalimages may be generated utilizing various imaging techniques, such asray-casting, maximum intensity pixel projection and the like.

The ultrasound system 200 of FIG. 6 may be embodied in a small-sizedsystem, such as laptop computer or pocket sized system as well as in alarger console-type system. FIGS. 8 and 9 illustrate small-sizedsystems, while FIG. 10 illustrates a larger system.

FIG. 8 illustrates a 3D-capable miniaturized ultrasound system 300having a probe 332 that may be configured to acquire 3D ultrasonic dataor multi-plane ultrasonic data. For example, the probe 332 may have a 2Darray of elements 104 as discussed previously with respect to the probe206 of FIG. 6. A user interface 334 (that may also include an integrateddisplay 336) is provided to receive commands from an operator. As usedherein, “miniaturized” means that the ultrasound system 330 is ahandheld or hand-carried device or is configured to be carried in aperson's hand, pocket, briefcase-sized case, or backpack. For example,the ultrasound system 330 may be a hand-carried device having a size ofa typical laptop computer. The ultrasound system 330 is easily portableby the operator. The integrated display 336 (e.g., an internal display)is configured to display, for example, one or more medical images.

The ultrasonic data may be sent to an external device 338 via a wired orwireless network 340 (or direct connection, for example, via a serial orparallel cable or USB port). In some embodiments, the external device338 may be a computer or a workstation having a display, or the DVR ofthe various embodiments. Alternatively, the external device 338 may be aseparate external display or a printer capable of receiving image datafrom the hand carried ultrasound system 330 and of displaying orprinting images that may have greater resolution than the integrateddisplay 336.

FIG. 9 illustrates a hand carried or pocket-sized ultrasound imagingsystem 350 wherein the display 352 and user interface 354 form a singleunit. By way of example, the pocket-sized ultrasound imaging system 350may be a pocket-sized or hand-sized ultrasound system approximately 2inches wide, approximately 4 inches in length, and approximately 0.5inches in depth and weighs less than 3 ounces. The pocket-sizedultrasound imaging system 350 generally includes the display 352, userinterface 354, which may or may not include a keyboard-type interfaceand an input/output (I/O) port for connection to a scanning device, forexample, an ultrasound probe 356. The display 352 may be, for example, a320×320 pixel color LCD display (on which a medical image 390 may bedisplayed). A typewriter-like keyboard 380 of buttons 382 may optionallybe included in the user interface 354.

Multi-function controls 384 may each be assigned functions in accordancewith the mode of system operation (e.g., displaying different views).Therefore, each of the multi-function controls 384 may be configured toprovide a plurality of different actions. Label display areas 386associated with the multi-function controls 384 may be included asnecessary on the display 352. The system 350 may also have additionalkeys and/or controls 388 for special purpose functions, which mayinclude, but are not limited to “freeze,” “depth control,” “gaincontrol,” “color-mode,” “print,” and “store.”

One or more of the label display areas 386 may include labels 392 toindicate the view being displayed or allow a user to select a differentview of the imaged object to display. The selection of different viewsalso may be provided through the associated multi-function control 384.The display 352 may also have a textual display area 394 for displayinginformation relating to the displayed image view (e.g., a labelassociated with the displayed image).

It should be noted that the various embodiments may be implemented inconnection with miniaturized or small-sized ultrasound systems havingdifferent dimensions, weights, and power consumption. For example, thepocket-sized ultrasound imaging system 350 and the miniaturizedultrasound system 300 may provide the same scanning and processingfunctionality as the system 200 (shown in FIG. 6)

FIG. 10 illustrates an ultrasound imaging system 400 provided on amovable base 402. The portable ultrasound imaging system 400 may also bereferred to as a cart-based system. A display 404 and user interface 406are provided and it should be understood that the display 404 may beseparate or separable from the user interface 406. The user interface406 may optionally be a touchscreen, allowing the operator to selectoptions by touching displayed graphics, icons, and the like.

The user interface 406 also includes control buttons 408 that may beused to control the portable ultrasound imaging system 400 as desired orneeded, and/or as typically provided. The user interface 406 providesmultiple interface options that the user may physically manipulate tointeract with ultrasound data and other data that may be displayed, aswell as to input information and set and change scanning parameters andviewing angles, etc. For example, a keyboard 410, trackball 412 and/ormulti-function controls 414 may be provided.

It should be noted that the various embodiments may be implemented inhardware, software or a combination thereof. The various embodimentsand/or components, for example, the modules, or components andcontrollers therein, also may be implemented as part of one or morecomputers or processors. The computer or processor may include acomputing device, an input device, a display unit and an interface, forexample, for accessing the Internet. The computer or processor mayinclude a microprocessor. The microprocessor may be connected to acommunication bus. The computer or processor may also include a memory.The memory may include Random Access Memory (RAM) and Read Only Memory(ROM). The computer or processor further may include a storage device,which may be a hard disk drive or a removable storage drive, solid-statedrive, optical disk drive, and the like. The storage device may also beother similar means for loading computer programs or other instructionsinto the computer or processor.

As used herein, the term “computer” or “module” may include anyprocessor-based or microprocessor-based system including systems usingmicrocontrollers, reduced instruction set computers (RISC), ASICs, logiccircuits, and any other circuit or processor capable of executing thefunctions described herein. The above examples are exemplary only, andare thus not intended to limit in any way the definition and/or meaningof the term “computer”.

The computer or processor executes a set of instructions that are storedin one or more storage elements, in order to process input data. Thestorage elements may also store data or other information as desired orneeded. The storage element may be in the form of an information sourceor a physical memory element within a processing machine.

The set of instructions may include various commands that instruct thecomputer or processor as a processing machine to perform specificoperations such as the methods and processes of the various embodimentsof the invention. The set of instructions may be in the form of asoftware program. The software may be in various forms such as systemsoftware or application software and which may be embodied as a tangibleand non-transitory computer readable medium. Further, the software maybe in the form of a collection of separate programs or modules, aprogram module within a larger program or a portion of a program module.The software also may include modular programming in the form ofobject-oriented programming. The processing of input data by theprocessing machine may be in response to operator commands, or inresponse to results of previous processing, or in response to a requestmade by another processing machine.

As used herein, the terms “software” and “firmware” are interchangeable,and include any computer program stored in memory for execution by acomputer, including RAM memory, ROM memory, EPROM memory, EEPROM memory,and non-volatile RAM (NVRAM) memory. The above memory types areexemplary only, and are thus not limiting as to the types of memoryusable for storage of a computer program.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the variousembodiments without departing from their scope. While the dimensions andtypes of materials described herein are intended to define theparameters of the various embodiments, the embodiments are by no meanslimiting and are exemplary embodiments. Many other embodiments will beapparent to those of skill in the art upon reviewing the abovedescription. The scope of the various embodiments should, therefore, bedetermined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled. In the appendedclaims, the terms “including” and “in which” are used as theplain-English equivalents of the respective terms “comprising” and“wherein.” Moreover, in the following claims, the terms “first,”“second,” and “third,” etc. are used merely as labels, and are notintended to impose numerical requirements on their objects. Further, thelimitations of the following claims are not written inmeans-plus-function format and are not intended to be interpreted basedon 35 U.S.C. §112, sixth paragraph, unless and until such claimlimitations expressly use the phrase “means for” followed by a statementof function void of further structure.

This written description uses examples to disclose the variousembodiments, including the best mode, and also to enable any personskilled in the art to practice the various embodiments, including makingand using any devices or systems and performing any incorporatedmethods. The patentable scope of the various embodiments is defined bythe claims, and may include other examples that occur to those skilledin the art. Such other examples are intended to be within the scope ofthe claims if the examples have structural elements that do not differfrom the literal language of the claims, or if the examples includeequivalent structural elements with insubstantial differences from theliteral languages of the claims.

What is claimed is:
 1. A method for monitoring a transducer array of anultrasound probe, the method comprising: acquiring ultrasound data usingan ultrasound probe when scanning patient tissue during an imaging modeof operation, the ultrasound data including echo information signalsacquired when scanning the patient tissue; utilizing one or moreprocessors to comparingcompare the echo informationsignals from aplurality of transducer elements of a transducer array of the ultrasoundprobe during the imaging mode of operation, the echo informationsignalsbeing non-beamformed signal data; and determiningdeterminenon-uniformity information for the transducer array using the comparedecho informationsignals during the imaging mode of operation.
 2. Themethod of claim 1, further comprising using utilizing the one or moreprocessors to use a threshold to determine valid ultrasound data echosignals for comparing.
 3. The method of claim 1, further comprisingaveraging utilizing the one or more processors to average a function ofthe acquired ultrasound data over a determined time period.
 4. Themethod of claim 3, wherein the function comprises a relative channelsensitivity.
 5. The method of claim 1, further comprising determiningutilizing the one or more processors to determine probe health for theultrasound probe using the determined non-uniformity information.
 6. Themethod of claim 1, further comprising compensating utilizing the one ormore processors to compensate for non-uniformities in one or moretransducer elements of the plurality of transducer elements using thedetermined non-uniformity information.
 7. The method of claim 1, furthercomprising quantifying utilizing the one or more processors to quantifyan impact of non-uniformities using the determined non-uniformityinformation.
 8. The method of claim 1, further comprising generatingutilizing the one or more processors to generate feedback informationusing the determined non-uniformity information.
 9. The method of claim8, wherein the feedback information is based in part on a detected probeevent.
 10. The method of claim 9, wherein the detected probe event is anexcessive acceleration event.
 11. The method of claim 1, furthercomprising creating utilizing the one or more processors to create trendinformation using the determined non-uniformity information.
 12. Themethod of claim 1, further comprising storing the determinednon-uniformity information and allowing access to the stored determinednon-uniformity information by an ultrasound console not providingnon-uniformity information.
 13. The method of claim 1, furthercomprising updating utilizing the one or more processors to update probeinformation as a function of probe life using the determinednon-uniformity information.
 14. The method of claim 1, wherein thecomparing the echo information signals comprises comparing signalamplitude information for at least a subset of the plurality oftransducer elements.
 15. The method of claim 1, wherein determining thenon-uniformity information during the imaging mode of operationcomprises performing the determination during ultrasound dataacquisition.
 16. The method of claim 1, wherein the comparing isperformed on ultrasound data comprising data in a non-beamformed or theecho signals when in non-image formed state.
 17. The method of claim 1,further comprising determining utilizing the one or more processors todetermine one of a health state or performance index of the ultrasoundprobe using the determined non-uniformity information and storing thedetermined health state or performance index in a memory, wherein thedetermined health state or performance index is linked to the ultrasoundprobe.
 18. An ultrasound system comprising: an ultrasound probe having atransducer array for acquiring ultrasound data including echoinformation during an imaging mode of operation; a memory for storingreceived echo information; and a monitoring module for comparing theecho information from a plurality of transducer elements of thetransducer array of the ultrasound probe during the imaging mode ofoperation, the stored echo information being non-beamformed signal data,the monitoring module also determining non-uniformity information forthe transducer array using the compared echo information during theimaging mode of operation.
 19. The ultrasound system of claim 18,wherein the monitoring module at least one of (i) uses apriori responsedata to predict an image quality deterioration, (ii) determines probehealth for the ultrasound probe using the determined non-uniformityinformation, (iii) compensates for non-uniformities in one or moretransducer elements of the plurality of transducer elements using thedetermined non-uniformity information, (iv) quantifies an impact ofnon-uniformities using the determined non-uniformity information; (v)generates feedback information using the determined non-uniformityinformation or (vi) creates trend information using the determinednon-uniformity information.
 20. The ultrasound system of claim 18,wherein the memory stores the determined non-uniformity information andallows access to the stored determined non-uniformity information by anultrasound console not providing non-uniformity information.
 21. Theultrasound system of claim 18, wherein the monitoring module comparessignal amplitude information for at least a subset of the plurality oftransducer elements.
 22. A non-transitory computer readable storagemedium for monitoring a transducer array of an ultrasound probe using aprocessor during an imaging mode of operation, the non-transitorycomputer readable storage medium including instructions to command theprocessor to: compare echo information from a plurality of transducerelements of a transducer array of an ultrasound probe during the imagingmode of operation, the echo information being non-beamformed signaldata; and determine non-uniformity information for the transducer arrayusing the compared echo information during the imaging mode ofoperation.
 23. The method of claim 1, wherein the ultrasound data isstored before performing the compare and determine operations.
 24. Themethod of claim 1, further comprising acquiring the ultrasound data overmultiple measurement sessions, wherein the compare operation isperformed with the ultrasound data from the multiple measurementsessions.
 25. The method of claim 24, wherein the ultrasound data isacquired over the multiple measurement sessions in connection with atleast one of different scanning views, different subjects or differentmachine setups.
 26. The method of claim 24, wherein the compareoperation comprises calculating, over a time window, at least one of anaverage magnitude, an accumulated sum of signal magnitude or astatistical measure of individual channels from the ultrasound probe.